Apollo A6L Lunar Overboots

The exhibit included some older, development versions of the Apollo lunar overboot.

There were a number of development Apollo space suit designs prior to the familiar Apollo A7L space suit, including the A6L suit. The lunar overboots from the A6L went through several design cycles and shared some similarities with the A7L/A7LB boot, yet the early A6L differed in a number of ways:

• The A7L/A7LB boots had an outer layer of woven chromium steel fabric called Chromel-R to improve thermal shielding and protect against abrasion;
• The A6L had a zipper at the rear to facilitate donning, whereas the A7L had extra fabric at the top of the front to allow the PGA boot to enter; this extra fabric would then be gathered and fastened together with two snaps; an additional retaining strap at the ankle and a strap assembly and latch on the instep held the boot in place;
• The toe area of the molded silicone sole on the A7L is higher than the initial A6L design, to provide more room and reduce internal abrasion and wear of the space suit at the toe;
• The vertical ribs at the nose of the boot went all the way to the bottom of the sole in the A6L boots, becoming part of the tread pattern whereas the durability of the A7L's nose was improved by shortening these ribs and using a smoother, more substantial lower toe;
• The A7L boot's bottom tread was modified slightly to further strengthen the heel and toe areas by extending the width of the crescent-shaped toe and heel ribs to the edge of the sole.

The A6L suit and boot designs were fluid, with various changes being incorporated along the way while still being called an "A6L". "Tall" (calf length) versions of the A6L were constructed, as well as the "short" (ankle length) A6L lunar overboots in this display. A6L boots produced later in the process featured some of the changes mentioned above, but all of the A6Ls retained the rear entry zipper.

Also see my page on the Apollo A7L/A7LB lunar overboot and Moon Boot: The Story of the Apollo Lunar Overshoe and the Race to Walk on the Moon (from which much of the descriptive text regarding the differences in the sole design was taken).